JP6107012B2 - Antenna design method - Google Patents

Description

  The present invention relates to an antenna design method, an antenna design apparatus, and an antenna design program.

  There is a wireless communication technique for improving communication quality by using an antenna including a plurality of antenna elements as a transmission / reception antenna mounted on a communication device such as a portable information terminal device. Multiple-input Multiple-output (MIMO) is an example of such wireless communication technology.

An antenna including a plurality of antenna elements is designed by the following antenna design method, for example.
First, the designer creates a model of a single antenna including a plurality of antenna elements.

  The designer acquires the antenna characteristics of the created single antenna model by simulation using an electromagnetic field simulator. The acquired antenna characteristics include antenna impedance, radiation efficiency, total efficiency, and the like.

  Next, the designer creates a model of each matching circuit connected to a plurality of antenna elements with reference to the characteristics of the acquired single antenna model. Then, the designer adds the created model of each matching circuit to the single antenna model, and acquires the antenna characteristics of the model to which the matching circuit is added using an electromagnetic field simulator.

  The designer evaluates whether or not the acquired antenna characteristics satisfy a desired standard. When evaluating that the antenna characteristics of the antenna model to which the matching circuit is added satisfy the desired standard, the designer ends the antenna design. On the other hand, when evaluating that the antenna characteristics do not satisfy a desired standard, the designer recreates a model of each matching circuit connected to the plurality of antenna elements, and continues the antenna design.

There is a conventional technique for measuring the radiation characteristics of a patch antenna using predetermined parameters including the conductivity of a transparent conductive film serving as a radiating element and the conductivity of a microstrip line.
There are conventional techniques for measuring the radiation efficiency of matching elements and antennas of transmission and / or reception modules.

  For a notch antenna including a reactance circuit, there is a conventional technique for obtaining a relationship between frequency and return loss and a relationship between frequency and antenna efficiency by electromagnetic field simulation such as a finite difference time domain method (FDTD) method.

JP 2008-306552 A Special table 2005-516525 gazette JP 2010-62976 A

  In recent years, portable information terminal devices have been reduced in size and thickness, and the space for mounting an antenna provided in the portable information terminal device has also been reduced in size and thickness. A portable information terminal device that has been reduced in size and thickness can have a structure in which an antenna and a peripheral component made of metal approach each other. When metal is present near the antenna, a current that cancels the antenna current flows through the metal, which causes deterioration of antenna performance.

An antenna performance index is a radiation resistance R _r . When the loss resistance included in the antenna and the matching circuit is R ₁ , the radiation efficiency η, which is the ratio between the net power applied to the antenna and the power radiated from the antenna, is expressed by the following equation (1). The

As is clear from equation (1), when the radiation resistance R _{r of the} antenna is small, the radiation efficiency η is greatly degraded even if the loss resistance R _l is a small value. Therefore, it is desirable to design the antenna so that the radiation resistance R _r is increased.

However, as described above, since a metal can exist near the antenna in the downsized and thin portable information terminal device, a structure that hardly emits radio waves, that is, a structure that has a small radiation resistance _Rr can be obtained. Therefore, when designing an antenna having a structure with a small radiation resistance R _r , it is necessary to pay attention to the loss resistance R ₁ even if it is a small value.

When the input impedance of the antenna deviates from the characteristic impedance (for example, 50Ω), it is necessary to perform matching by a matching circuit. The matching element constituting the matching circuit includes a slight resistance component in addition to the capacitance component or inductance component and the parasitic inductance component or parasitic capacitance component. Therefore, when designing an antenna having a structure with a small radiation resistance R _r , it is necessary to consider the resistance component of each matching element constituting the matching circuit.

  In addition, when an antenna including a plurality of antenna elements as described above is mounted on a miniaturized and thin portable information terminal device, the arrangement interval between the antenna elements is narrowed. Can occur. When electromagnetic coupling occurs between the antenna elements, the antenna characteristics are degraded such as a decrease in radiation efficiency. Therefore, when the antenna to be designed includes a plurality of antenna elements, it is necessary to design the antenna in consideration of the interaction between the antenna elements such as the isolation characteristics between the antenna elements.

  However, in the conventional antenna design method described above, it is not possible to quickly and efficiently perform antenna design that takes into account the interaction between antenna elements and the loss of matching circuits connected to individual antenna elements.

  That is, in the conventional antenna design method described above, the antenna characteristics of an antenna model including a matching circuit connected to each of a plurality of antenna elements are obtained by simulation. For this reason, in the conventional antenna design method, it takes an enormous amount of time to calculate the antenna characteristics in consideration of the interaction between the antenna elements and the loss of the matching circuit. Therefore, with the conventional antenna design method, it is not possible to quickly design an antenna that satisfies a desired standard.

  Further, in the conventional antenna design method described above, the designer evaluates whether or not the simulation result conforms to a desired standard, and the designer needs to reconsider the configuration of the matching circuit based on the evaluation result. For this reason, in the conventional antenna design method, it is not possible to quickly and efficiently perform an antenna design that takes into account the interaction between antenna elements and the loss of the matching circuit.

  An object of the present invention is to quickly and efficiently perform an antenna design that takes into account the interaction between antenna elements and the loss of matching elements.

According to one embodiment, a computer includes an antenna including a plurality of antenna elements, and a matching circuit connected to each of the plurality of antenna elements, the matching circuit including parasitic reactances and loss resistors. Create an antenna model containing. Further, the computer acquires the characteristics of the antenna and the characteristics of the matching element, and calculates the characteristics of the created antenna model using the acquired characteristics of the antenna and the characteristics of the matching element. Then, the computer determines whether or not the calculated characteristics of the antenna model satisfy a desired standard value, and displays the determined result. Here, the characteristic of the antenna model includes the S parameter of the antenna and the total efficiency of the antenna model, the characteristic of the matching element includes the impedance of the matching element, and the characteristic of the antenna model includes the S parameter of the antenna model. In calculating the characteristics of the antenna model, the computer calculates the F parameter of the antenna using the S parameter of the antenna, calculates the F parameter of the matching circuit using the impedance of the matching element, and calculates the F of the antenna. The S parameter of the antenna model is calculated using the parameters and the F parameter of the matching circuit, and the ratio of the radiation efficiency of the antenna and the sum of the loss of the antenna and the radiation efficiency is regarded as the same for the model of the antenna alone and the antenna model Then, the total efficiency of the antenna model is calculated .

  According to the embodiment, it is possible to quickly and efficiently perform antenna design that takes into account the interaction between antenna elements and the loss of matching elements.

It is a functional block diagram of the antenna design apparatus according to the embodiment. It is a schematic block diagram of an antenna model with an exemplary matching circuit. FIG. 3 is an equivalent circuit diagram of the antenna model with a matching circuit shown in FIG. 2. FIG. 4 is an equivalent circuit diagram of the first and second circuits shown in FIG. 3. FIG. 3 is an exemplary equivalent circuit diagram of a first line and a second line. It is an example figure of the 1st and 2nd matching circuit. It is an equivalent circuit diagram of an exemplary antenna unit model. It is explanatory drawing of the antenna model with a matching circuit used for verification of calculation accuracy. FIG. 9 is an equivalent circuit diagram of the antenna model with a matching circuit shown in FIG. 8. I am a frequency characteristic diagram of the S ₁₁ in the first test example. Is a Smith chart of S ₁₁ in the first test example. It is a frequency characteristic diagram of the S ₂₂ in the first test example. Is a Smith chart of S ₂₂ in the first test example. It is a frequency characteristic diagram of the S ₂₁ and S ₁₂ in the first test example. It is a frequency characteristic figure of the radiation efficiency of the 1st antenna element in the 1st verification example. It is a frequency characteristic figure of the total efficiency of the 1st antenna element in the 1st verification example. It is a frequency characteristic figure of the radiation efficiency of the 2nd antenna element in the 1st verification example. It is a frequency characteristic figure of the total efficiency of the 2nd antenna element in the 1st verification example. The reference impedance Z ₀₂ of the second port is a frequency characteristic diagram of the S ₁₁ cases was zero. The reference impedance Z ₀₂ of the second port is a frequency characteristic diagram of the total efficiency of the first antenna element of the case was zero. It is a frequency characteristic diagram of the S ₁₁ of the case in which the reference impedance Z ₀₂ of the second port is infinite. It is a frequency characteristic diagram of the total efficiency of the first antenna element of the case where the reference impedance Z ₀₂ of the second port is infinite. It is an example figure of the antenna design processing flow according to an embodiment. It is an example of the display screen of the antenna model design tool with a matching circuit. It is an example figure of the exchange process flow of a matching element. It is an example figure of the change process flow of the track length of a track. It is a hardware block diagram of the computer which performs the antenna design program according to embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 is a functional configuration diagram of an antenna design apparatus according to an embodiment.
The antenna design apparatus 100 shown in FIG. 1 is an apparatus that performs antenna design in consideration of the interaction between antenna elements and the loss of matching elements.

  As will be described later, when the antenna design is performed in consideration of the interaction between the antenna elements and the loss of the matching element, the antenna design apparatus 100 uses the antenna characteristics of the model including the antenna and the matching circuit according to the embodiment. Calculated by analytical method.

  In some embodiments, the antenna design apparatus 100 takes into account the loss of the feed line between the antenna element and the wave source (signal source) in addition to the interaction between the antenna elements and the loss of the matching element. Execute.

  The line connecting the antenna element and the transmission / reception module as the wave source may include a loss. For example, when the portable information terminal device is thinned, the thickness of the line may be thin. Since the loss of the line becomes larger as the thickness of the line becomes thinner, the radiation efficiency η of the antenna can be deteriorated by the influence of the loss of the line. Therefore, depending on the thickness of the feed line to be connected to the antenna, it is necessary to perform antenna design in consideration of the line loss.

  As will be described later, when antenna design is performed in consideration of the loss of the line in addition to the interaction between the antenna elements and the loss of the matching element, the antenna design device 100 includes the antenna, the matching circuit, and the line. The antenna characteristics of the included model are calculated by an analytical method according to the embodiment.

  The antenna design apparatus 100 includes an input unit 110, a storage unit 120, a processing unit 130, and a display unit 140.

  The input unit 110 is a device for inputting various data necessary for antenna design. The input unit 110 is, for example, a keyboard or a mouse.

  The various data input via the input unit 110 includes data related to the model shape, model material, wave source, circuit components, analysis conditions, and analysis output items.

  The data relating to the material of the model is, for example, data relating to conductivity, dielectric constant, magnetic permeability, various losses, and the like. The data relating to the analysis conditions is, for example, data relating to the upper and lower limits of the frequency to be analyzed, the frequency increment, and the presence / absence of high-speed processing setting. The data relating to the analysis output item is, for example, data relating to S parameter (Scattering parameter), radiation efficiency, and total efficiency. In addition, the data regarding the analysis output item may include the antenna impedance and the impedance of the matching element, and may include the characteristic impedance and transfer coefficient of the line depending on the embodiment.

  In the model including the antenna and the matching circuit, the radiation efficiency is a ratio between the net power entering the antenna (powered antenna element) at the insertion position of the matching circuit on the wave source side and the radiation power from the antenna. In the model including the antenna, matching circuit, and line, the radiation efficiency is the ratio between the net power that enters the antenna (powered antenna element) at the insertion position of the line on the wave source side and the radiated power from the antenna. is there. In a model of a single antenna that does not include a line and a matching circuit, the radiation efficiency is the ratio of the net power entering the antenna (powered antenna element) and the radiated power from the antenna.

  The total efficiency refers to the ratio between the total input power from the wave source and the radiated power from the antenna (powered antenna element).

  The storage unit 120 is a storage device that includes an antenna characteristic file 121 and a calculation processing data file 123 in which processing data by the processing unit 130 is stored.

  In an embodiment in which the antenna design apparatus 100 performs antenna design in consideration of line loss, the storage unit 120 may further include a line characteristic file 122.

  In some embodiments, the storage unit 120 further includes a matching element data file 124. The matching element data file 124 stores, for example, various data of matching elements that are commercially available from circuit component manufacturers and the like. As an example of various data of the matching element to be stored, data on the type of matching element, the capacitance or inductance of the matching element, the size of the matching element, parasitic inductance or parasitic capacitance, loss resistance, withstand voltage, price, etc. Is mentioned.

  The storage unit 120 is, for example, a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD).

  The processing unit 130 is a device that executes an antenna design process according to the embodiment. The processing unit 130 is, for example, a Central Processing Unit (CPU).

  The display unit 140 is a device that performs display for prompting input to the input unit 110 and displays a processing result by the processing unit 130. The display unit 140 is, for example, a liquid crystal display device.

  The processing unit 130 includes an antenna characteristic simulation processing unit 131 and an antenna characteristic calculation processing unit 133. In the embodiment in which the antenna design apparatus 100 performs antenna design in consideration of line loss, the processing unit 130 further includes a line characteristic calculation processing unit 132.

  The antenna characteristic simulation processing unit 131 includes an antenna model creation unit 131a without a matching circuit, a simulation execution unit 131b, and a simulation result determination unit 131c.

  The antenna model creation unit 131a without a matching circuit creates an antenna model that does not include a matching circuit in accordance with the input data input via the input unit 110.

  That is, in the embodiment in which the antenna design apparatus 100 executes antenna design in consideration of the interaction between the antenna elements and the loss of the matching element, the antenna model creation unit 131a without a matching circuit includes a single antenna model including a plurality of antenna elements. Create In the embodiment in which the antenna design apparatus 100 executes antenna design in consideration of the loss of the line between the antenna element and the wave source, the antenna model creation unit 131a without a matching circuit includes a single antenna including a plurality of antenna elements. A model and an antenna model in which a line is connected to the antenna are created.

  The simulation execution unit 131b executes a simulation for the antenna model created by the antenna model creation unit 131a without a matching circuit.

  The simulation executed by the simulation execution unit 131b is an electromagnetic field simulation using, for example, a moment method, a finite element method, a finite difference time domain method, or the like.

  The antenna characteristics for the antenna model not including the matching circuit are acquired by the simulation of the simulation execution unit 131b. The acquired antenna characteristics include the impedance, S parameter, radiation efficiency, and total efficiency for each frequency set by the input via the input unit 110. These antenna characteristics are stored in the antenna characteristic file 121 of the storage unit 120.

  The simulation result determination unit 131c determines whether or not the antenna characteristics of the single antenna model satisfy a desired standard when performing antenna design taking into account the interaction between antenna elements and the loss of the matching element. In the embodiment in which the antenna design is performed in consideration of the loss of the line, the simulation result determination unit 131c determines whether or not the antenna characteristics of the antenna model including the antenna and the line satisfy a desired standard.

  The determination result by the simulation result determination unit 131 c is stored in the antenna characteristic file 121.

  The line characteristic calculation processing unit 132 can be provided in the antenna design apparatus 100 in order to execute antenna design that also takes into account the loss of the line between the antenna element and the wave source.

  The line characteristic calculation processing unit 132 calculates the characteristic for the line model created according to the input via the input unit 110.

  The line characteristic calculation processing unit 132 includes a line model creation unit 132a and a line characteristic calculation unit 132b.

  The line model creation unit 132a obtains line data and board data set by input via the input unit 110, and creates a line model. The track data includes data related to the length and width of the track. The substrate data includes data on the relative dielectric constant, dielectric loss tangent, thickness, conductor height, dielectric constant, and the like of the substrate.

  The line characteristic calculation unit 132b calculates the characteristic impedance and transmission coefficient (attenuation constant and phase constant) of the line for each frequency set by the input through the input unit 110 for the line model created by the line model creation unit 132a. To do.

  Each data relating to the characteristic impedance and transmission coefficient (attenuation constant and phase constant) of the line calculated by the line characteristic calculation unit 132 b is stored in the line characteristic file 122.

  The antenna characteristic calculation processing unit 133 calculates the antenna characteristic of the antenna model including the matching circuit created according to the input through the input unit 110 using the calculation method according to the embodiment, and the calculated antenna characteristic is desired. It is determined whether or not the standard is satisfied.

  In the following description, “antenna model including a matching circuit” or “antenna model with a matching circuit” means that the antenna design apparatus 100 performs antenna design in consideration of the interaction between antenna elements and the loss of the matching element. In the embodiment, it refers to a model including an antenna and a matching circuit. The “antenna model including a matching circuit” or “antenna model with a matching circuit” is an embodiment in which the antenna design apparatus 100 performs antenna design in consideration of the loss of the line between the antenna element and the wave source. Refers to a model including an antenna, a line, and a matching circuit.

  The process by the antenna characteristic calculation processing unit 133 is executed when the antenna characteristic of the antenna model not including the matching circuit does not satisfy a desired standard value.

  That is, in the embodiment in which the antenna design apparatus 100 performs antenna design in consideration of the interaction between the antenna elements and the loss of the matching element, the process by the antenna characteristic calculation processing unit 133 is that the antenna characteristic of the single antenna model is desired. It is executed when the standard value is not satisfied. In the embodiment in which the antenna design apparatus 100 executes antenna design in consideration of the loss of the line between the antenna element and the wave source, the process by the antenna characteristic calculation processing unit 133 is performed for the antenna model including the antenna and the line. This is executed when the antenna characteristic does not satisfy a desired standard value.

  Depending on the embodiment, when the total efficiency at the target frequency of the antenna model not including the matching circuit is less than a desired standard value as a result of the determination by the simulation result determination unit 131c, the processing by the antenna characteristic calculation processing unit 133 is executed. Is done.

  Depending on the embodiment, the process by the antenna characteristic calculation processing unit 133 is executed regardless of the determination result by the simulation result determination unit 131c. For example, when the characteristics of a single antenna, the characteristics of each matching element constituting the matching circuit, and the characteristics of the line are acquired by any means, the antenna characteristic calculation processing unit 133 uses these acquired characteristics. To execute the process.

  The antenna characteristic calculation processing unit 133 includes an antenna model creation unit 133a with a matching circuit, an antenna characteristic calculation unit 133b, and a calculation result determination unit 133c.

  The antenna model creation unit 133a with a matching circuit creates an antenna model including a matching circuit.

  That is, in the embodiment in which the antenna design apparatus 100 performs antenna design in consideration of the interaction between the antenna elements and the loss of the matching element, the antenna model creation unit 133a with a matching circuit selects the antenna model including the antenna and the matching circuit. create. In the embodiment in which the antenna design apparatus 100 executes antenna design in consideration of the loss of the line between the antenna element and the wave source, the antenna model creation unit 133a with a matching circuit includes the antenna, the matching circuit, and the line. Create an antenna model that includes it.

  The antenna model creation unit 133a with a matching circuit imports the antenna characteristics of a single antenna stored in the antenna characteristics file 121. That is, the antenna model creation unit 133a with a matching circuit imports each data related to the antenna impedance, S parameter, and radiation efficiency for each target frequency.

  Depending on the embodiment, the antenna model creation unit 133a with a matching circuit imports each data related to the antenna impedance, S parameter, and radiation efficiency for each target frequency input via the input unit 110.

  The matching-circuit-equipped antenna model creation unit 133a calculates the circuit configuration of the matching circuit based on the imported antenna impedance. Depending on the embodiment, the antenna model creation unit 133a with a matching circuit acquires the data of the circuit configuration of the matching circuit input via the input unit 110.

  The matching-circuit-equipped antenna model creation unit 133a determines a matching element that constitutes the matching circuit that conforms to the use conditions such as size and breakdown voltage, according to the calculated or acquired circuit configuration. Data on usage conditions such as size and breakdown voltage is given in advance by input via the input unit 110 or the like.

  In some embodiments, the matching circuit-equipped antenna model creation unit 133a refers to matching element data stored in the matching element data file 124 to determine matching elements that constitute the matching circuit. Depending on the embodiment, the antenna model creation unit 133a with a matching circuit determines a matching element that matches the use condition based on the data of the matching element input via the input unit 110.

  The antenna model creation unit 133a with a matching circuit acquires a parasitic inductance or parasitic capacitance and a loss resistance in addition to the determined capacitance or inductance of the matching element.

  In some embodiments, the parasitic inductance or the parasitic capacitance and the loss resistance are obtained by referring to data of the corresponding matching element stored in the matching element data file 124. In some embodiments, the parasitic inductance or parasitic capacitance of the matching element and the loss resistance are obtained by being input via the input 110.

  Thus, in the embodiment, an antenna model with a matching circuit including the parasitic reactance and loss resistance of the matching element is created by the antenna model creation unit 133a with matching circuit. Each value including the parasitic reactance and the loss resistance of the matching element constituting the created matching circuit is acquired from the matching element data file 124 or designated by an input via the input unit 110.

  Therefore, according to the embodiment, in addition to the capacitance or inductance of each matching element constituting the matching circuit, each model of parasitic reactance and loss resistance is individually created, or the values are individually set. There is no need to do. Therefore, an antenna model with a matching circuit that takes into account the parasitic reactance and loss resistance of the matching element can be created quickly and efficiently.

  In an embodiment in which the antenna design apparatus 100 executes antenna design in consideration of the loss of the line between the antenna element and the wave source, the antenna model creation unit 133a with a matching circuit includes the line stored in the line characteristic file 122. Import characteristics. In other words, the antenna model creation unit 133a with a matching circuit imports each data related to the characteristic impedance and transmission coefficient (attenuation constant and phase constant) of the line for each target frequency. Further, in some embodiments, the antenna model creation unit 133a with a matching circuit receives each data related to the characteristic impedance and transmission coefficient (attenuation constant and phase constant) of the line for each target frequency input via the input unit 110. Import. The antenna model creation unit with matching circuit 133a creates an antenna model with matching circuit including a line having the imported characteristics.

  The antenna characteristic calculation unit 133b calculates the antenna characteristic of the antenna model with a matching circuit created by the antenna model creation unit 133a with a matching circuit according to the calculation method of the embodiment.

  That is, depending on the embodiment, the antenna characteristic calculation unit 133b calculates the antenna characteristic of the antenna model with a matching circuit in consideration of the loss of the matching element and the interaction between the antenna elements by an analytical method that does not use simulation. Further, depending on the embodiment, the antenna characteristic calculation unit 133b does not depend on the simulation of the antenna characteristic of the antenna model with the matching circuit in which the loss of the matching element and the interaction between the antenna elements are considered in addition to the loss of the line. Calculate by analytical methods.

  The antenna characteristics calculated by the antenna characteristic calculator 133b include S parameters, radiation efficiency, and total efficiency.

  Further, the antenna characteristic calculation unit 133b can calculate the power consumption of the matching element and the line included in the antenna model with a matching circuit.

  As an example of the antenna characteristic calculation method according to the embodiment, the antenna characteristic calculation unit 133b determines the antenna characteristic of the antenna model with a matching circuit, taking into account the loss of the matching element, the loss of the line, and the interaction between the antenna elements. The calculation method will be described below.

FIG. 2 is a schematic configuration diagram of an exemplary antenna model with a matching circuit.
As shown in FIG. 2, the antenna model 200 with a matching circuit includes an antenna 210. The antenna 210 includes a first antenna element 211 and a second antenna element 212.

  The first antenna element 211 is connected to the first antenna element side line 241-1 and is connected to the first matching circuit 231 via the first antenna element side line 241-1. The first antenna element 211 is connected to the first wave source side line 241-2 via the first antenna element side line 241-1 and the first matching circuit 231. The first antenna element 211 can be connected to the ground conductor 220 via the first antenna element side line 241-1, the first matching circuit 231, and the first wave source side line 241-2. A wave source (not shown) such as a transmission / reception module may be connected between the first wave source side line 241-2 and the ground conductor 220.

  The second antenna element 212 is connected to the second antenna element side line 242-1 and is connected to the second matching circuit 232 via the second antenna element side line 242-1. The second antenna element 212 is connected to the second wave source side line 242-2 via the second antenna element side line 242-1 and the second matching circuit 232. The second antenna element 212 can be connected to the ground conductor 220 via the second antenna element side line 242-1, the second matching circuit 232, and the second wave source side line 242-2. A wave source may be connected between the second wave source side line 242-2 and the ground conductor 220.

  As shown in FIG. 2, the signal input / output port of the first antenna element 211 is defined as a first port (port 1), and the signal input / output port of the second antenna element 212 is defined as a second port ( It is defined as port 2).

  FIG. 3 is an equivalent circuit diagram of the antenna model with a matching circuit shown in FIG. FIG. 3 shows, as an example, an equivalent circuit in the case where power is supplied from the first port to the first antenna element 211 and the power supply voltage of the second antenna element 212 is 0V.

  As shown in FIG. 3, the equivalent circuit 300 of the antenna model with a matching circuit includes an antenna 310, a first circuit 320-1, a second circuit 320-2, and a wave source 330.

  The antenna 310 is an equivalent circuit of the antenna 210 including the first antenna element 211 and the second antenna element 212.

  The first circuit 320-1 is an equivalent circuit of the first antenna element side line 241-1, the first matching circuit 231, and the first wave source side line 241-2. The second circuit 320-2 is an equivalent circuit of the second antenna element side line 242-1, the second matching circuit 232, and the second wave source side line 242-2.

  FIG. 4 is an equivalent circuit diagram of the first and second circuits shown in FIG. The first and second circuits 320-i (i is 1 or 2) shown in FIG. 4 include a matching circuit 321-i, a first line 322-i, and a second line 323-i. The matching circuit 321-i corresponds to the first matching circuit 231 and the second matching circuit 232, respectively. The first line 322-i corresponds to the first antenna element side line 241-1 and the second antenna element side line 242-1, respectively. The second line 323-i corresponds to the first wave source side line 241-2 and the second wave source side line 242-2, respectively.

Z ₀₁ shown in FIG. 3 is the reference impedance of the first port, and Z ₀₂ is the reference impedance of the second port. The reference impedance Z ₀₁ of the first port and the Z ₀₂ of the second port are, for example, equal to the reference impedance Z ₀ and can be 50 ohms (Ω) (Z ₀₁ = Z ₀₂ = Z ₀ = 50Ω). In the example illustrated in FIG. 3, the internal impedance of the wave source 240 matches the reference impedance Z ₀₁ .

First, a method for calculating the S parameter of the antenna model with a matching circuit according to the embodiment will be described.
In FIG. 3, F _a indicates an F parameter (Fundamental parameter) of the antenna 310 alone. F _ml1 refers to F parameter of the first circuit 320-1, F _ml2 refers to F parameters of the second circuit 320 - 2.

The F parameter F _a of the antenna 310 alone can be calculated from the S parameter S _a of the antenna 310 alone. S-parameter S _a of the antenna 310 itself is defined by the following equation (2).

Of the elements of the S parameter S _a of the antenna 310 alone, S _a21 is a transfer coefficient from the first port to the second port. The transfer coefficient S _a21 from the first port to the second port is included in the isolation characteristic between the first antenna element 211 and the second antenna element 212.

Antenna 310 single F parameter F _a can be calculated from equation (2) using the following equation (3).

As described above, in the embodiment, S parameter S _a unitary antenna 310 is a known value. That is, in some embodiments, antenna 310 single S-parameter S _a is, in some embodiments, is obtained by simulation of the simulation execution portion 131b is stored in the antenna characteristic file 121. In some embodiments, S parameter S _a unitary antenna 310 is acquired by the input by the input unit 110. Further, the value of Z ₀ (the values of Z ₀₁ and Z ₀₂ ) is set by input via the input unit 110. Accordingly, the F parameter F _a of the antenna 310 alone can be calculated by substituting the known S parameter S _a of the antenna 310 into Equation (3).

In FIG. 4, F _mli corresponds to the F parameter F _ml1 of the first circuit 320-1 and the F parameter F _ml2 of the second circuit 320-2 _shown in FIG. F _mi indicates the F parameter of the first and second matching circuits 321-i. F _li1 indicates the F parameter of the first line 322-i, and F _li2 indicates the F parameter of the second line 323-i.

FIG. 5 is an exemplary equivalent circuit diagram of the first line and the second line. When the first line 322-i and the second line 323-i are regarded as distributed constant lines, and the lengths of the first line 322-i and the second line 323-i are x, FIG. It can be expressed by an equivalent circuit 400 of a transmission line as shown. As shown in FIG. 5, the transmission line equivalent circuit 400 includes an inductor L _dx connected in series, a capacitor C _dx connected in parallel, a resistance R _dx as a series loss, and a conductance as a parallel loss. Includes G _dx .

The characteristic of the equivalent circuit 400 of the transmission line shown in FIG. 5 is given by solving the telegraph equation. In order to clarify the explanation, a transmission line in the case of a lossless and steady state will be described as an example. As shown in FIG. 5, when the starting current and voltage are I _x1 and V _x1 , and the terminating current and voltage are I _x2 and V _x2 , respectively, the following equation (4) is established.

F _x in equation (4) is an F parameter of a transmission line having a length x. Z ₀ is characteristic impedance, Y ₀ is admittance, and is 1 / Z ₀ . γ is a transfer coefficient, and is expressed by the following equation (5), where β is the phase constant of the transmission line.

As described above, in the embodiment, the line length l _i1 , characteristic impedance Z _il1 , attenuation constant α _i1 , and phase constant β _i1 of the first line 322-i are known values. The line length l _i2 , characteristic impedance Z _il2 , attenuation constant α _i2 , and phase constant β _i2 of the second line 323-i are known values. That is, the line lengths l _i1 and l _i2 are acquired by the input of the input unit 110, respectively. Further, the characteristic impedances Z _il1 and Z _il2 , the attenuation constants α _i1 and α _i2 , and the phase constants β _i1 and β _i2 are obtained by calculation of the line characteristic calculation unit 132b and stored in the line characteristic file 122 in some embodiments. In some embodiments, it is acquired by input via the input unit 110.

Therefore, F parameter F _li2 the F parameter F _li1 and second line 323-i of the first line 322-i, for example, can be calculated respectively using the above equation (5).

FIG. 6 is an example of first and second matching circuits.
For example, assume that the first and second matching circuits 321-i include three matching elements 321 a, 321 b, and 321 c shown in FIG. 6, and these matching elements are connected in a pi (π) type. Three matching elements 321a, 321b, and 321c admittance of Y _mi1, Y _mi2, and respectively when defined as Y _mi3, F parameter F _mi of the first and second matching circuits 321-i, the following equation (6 ) Respectively.

As described above, in the embodiment, the loss resistance R _mij and the reactance X _mij constituting the impedance Z _mij of each of the three matching elements 321a, 321b, and 321c are known values (an example shown in FIG. 6). Then, j is an integer of 1 to 3). That is, in some embodiments, these values are obtained by referring to matching element data stored in the matching element data file 124. In some embodiments, these values are acquired by input via the input unit 110. The impedances Z _mij of the three matching elements 321a, 321b, and 321c can be calculated by the following formula (7) using the loss resistance R _mij and the reactance X _mij that are known values, respectively.

Further, the admittance Y _mij of each matching element included in the first and second matching circuits 321-i can be obtained by calculating the reciprocal of the value of the impedance Z _mij calculated by the equation (7).

Accordingly, the F parameter F _mi of the first and second matching circuits 321-i can be calculated by the equation (6), respectively.

  Note that the first and second matching circuits 321-i shown in FIG. 6 are examples, and the number of matching elements included in the first and second matching circuits 321-i is limited to three. Does not mean. Further, it does not mean that the first and second matching circuits 321-i are limited to a matching circuit in which matching elements are connected in a pie shape as shown in FIG. 6. The circuit configuration of the first matching circuit 321-1 may be different from the circuit configuration of the second matching circuit 321-2.

Depending on the embodiment, the antenna characteristic calculation unit 133b executes the following calculation process in addition to the calculation process of the F parameter F _mi of the first and second matching circuits 321-i as described above. It is also possible. That is, the antenna characteristic calculation unit 133b calculates the F parameter F _mi of the first and second matching circuits 321-i in consideration of the impedance of the via in addition to the impedance of the matching element.

  For example, matching elements mounted in parallel to the antenna 310, such as the matching element 321a and the matching element 321b shown in FIG. 6, are connected to the ground conductor via the ground via. When the impedances of the ground vias connected to these matching elements cannot be ignored, the antenna characteristic calculation unit 133b calculates the antenna characteristics of the antenna model 200 with a matching circuit in consideration of the impedances of these vias. That is, the antenna characteristic calculation unit 133b calculates the antenna characteristic of the antenna model 200 with a matching circuit in consideration of the via inductance and / or resistance.

For example, when the ground via has a cylindrical shape, the antenna characteristic calculation unit 133b calculates the inductance L _{v of the} ground via according to the following equation (8).

In Equation (8), μ ₀ is the vacuum permeability. h is the length of the via. r is the radius of the via. When the via diameter is D, r = D / 2.

For example, when the antenna model creation unit 133a with a matching circuit calculates or acquires a circuit configuration in which the matching element is mounted in parallel with the antenna 310, the display unit 140 inputs each value of the via length h and the via diameter D. A display prompting Each value of the via length h and the via diameter D is input via the input unit 110. Antenna characteristic calculation section 133b calculates the inductance L _v of the via using each value of the input via length h and the via diameter D.

For example, when the ground via has a cylindrical shape, the antenna characteristic calculation unit 133b calculates the resistance R _{v of the} ground via according to the following equation (9).

In Equation (9), f is the signal frequency, and R _v0 is the direct current resistance of the via. Further, f _δ in the equation (9) is expressed by the following equation (10).

  In equation (10), ρ is the resistivity of the conductor. t is the thickness of the metallization in the via. When the via diameter D is the outer diameter of the via and the inner diameter of the via is D ′, t = DD ′.

For example, when the antenna model creation unit with matching circuit 133a calculates or acquires a circuit configuration in which the matching element is mounted in parallel with the antenna 210, the display unit 140 displays the via outer diameter D, the via inner diameter D ′, A display prompting input of each value of resistivity ρ and DC resistance R _v0 is displayed. The values of the outer diameter D of the via, the inner diameter D ′ of the via, the resistivity ρ, and the direct current resistance R _v0 are input via the input unit 110. Antenna characteristic calculation unit 133b, the outer diameter D of the input via, the inner diameter of the via D', resistivity [rho, and calculates a resistance R _v of the via using the values of DC resistance R _v0.

The antenna characteristic calculator 133b adds the reactance of the matching element that connects the calculated via inductance _Lv to the via to X _mij . The antenna characteristic calculation unit 133b adds a loss resistance of the matching element to be connected to the via resistance R _v of the calculated via the R _mij. The calculation method of the F parameter F _mi of the first and second matching circuits 321-i executed after the addition of the via inductance L _v and / or the via resistance R _v is the same as described above.

The F parameter F _mli of the first and second circuits 320-i shown in FIG. 3 is the calculated F parameter F _{mi of} the first and second matching circuits 321-i and of the first line 322-i. with F parameter F _li1, and F parameters F _li2 the second line 323-i can be calculated respectively by the following equation (11).

Further, the combined F parameter F _mla of the equivalent circuit 300 of the antenna model with a matching circuit includes the calculated F parameter F _a of the antenna 310 alone, the F parameter F _ml1 of the first circuit _320-1 , and the second circuit 320. -2 can be calculated by the following formula (12) using the F parameter F _{ml2 of} -2.

The S parameter S _mla of the equivalent circuit 300 of the antenna model with a matching circuit can be calculated by the following equation (13) using the calculated combined F parameter F _mla .

S ₂₁ in the equation (13) is a transfer coefficient from the first port to the second port in the antenna model 200 with a matching circuit. The transfer coefficient S ₂₁ from the first port to the second port is included in the isolation characteristic between the first antenna element 211 and the second antenna element 212.

As shown in FIG. 3, the S parameter S _mla calculated by the equation (13) is fed from the first port to the first antenna element 211 and the feeding voltage of the second antenna element 212 is 0V. S parameter.

On the other hand, the S parameter in the case where power is supplied from the second port to the second antenna element 212 and the power supply voltage of the first antenna element 211 is 0 V is the inverse matrix F _mla ⁻¹ of the F parameter F _mla. And can be obtained by calculating according to equation (13) using the calculated F _mli ⁻¹ .

Further, as described above, Z _{0 in} equation (13) is a reference impedance, for example, 50Ω. That is, the S parameter S _mla calculated by the equation (13) is an S parameter in the case where the values of Z ₀₁ and Z ₀₂ are both Z ₀ (Z ₀₁ = Z ₀₂ = Z ₀ ).

In contrast, 'S parameter S _mla case set to' the value of the reference impedance of the port that is not fed to the antenna elements as in the second port is Z ₀ of a value different from Z ₀ 3 Can be calculated by the S parameter conversion formula shown in the following formula (14). That is, using the S parameter S _mla of the case where both the values of Z ₀₁ and Z ₀₂ are set to Z ₀ , the value of the S parameter S _mla ′ of the case where the value of Z ₀₁ or Z ₀₂ is Z ₀ ′ is obtained. It can be calculated.

In formula (14), I represents a unit matrix, and W ⁻¹ represents an inverse matrix of W. W and Γ are diagonal matrices represented by the following equations (15) and (16), respectively.

Z ₀₁ ′ in the equations (15) and (16) is the changed reference impedance of the first port, that is, the reference impedance of the first port that can be changed to a value different from the reference impedance Z _0. . Z ₀₂ ′ is the reference impedance of the second port after the change. For example, in the equivalent circuit 300 of the antenna model with a matching circuit shown in FIG. 3, the reference impedance Z ₀₂ of the second port can be set to Z ₀₁ ′. Therefore, in the equivalent circuit 300 of the antenna model with a matching circuit shown in FIG. 3, the changed reference impedance Z ₀₁ ′ of the first port is Z ₀ , and the changed reference impedance Z ₀₂ of the second port. 'Is Z ₀ '.

However, when a port not fed to the antenna element is short-circuited, that is, when the value of Z ₀₁ ′ or Z ₀₂ ′ is 0, W ⁻¹ that is an inverse matrix of W does not exist. Further, when a port that is not supplied with power to the antenna element is opened, that is, when the value of Z ₀₁ ′ or Z ₀₂ ′ is infinite (∞), W ⁻¹ does not exist. Therefore, when the value of Z ₀₁ or Z ₀₂ is 0 or infinity, the following calculation is performed instead of the equation (14).

First, as shown in FIG. 3, in the case where power is supplied from the first port to the first antenna element 211 and the power supply voltage of the second antenna element 212 is 0 V, the input impedance when the value of Z ₀₂ is 0 Z ′ _{in_mla} is calculated by the following equation (17). Further, the input impedance Z ′ in — _mla when the value of Z ₀₂ is infinite is calculated by the following equation (18).

A _mla , B _mla , C _mla , and D _mla in the equations (17) and (18) are elements of the F parameter F _mla and can be calculated as shown in the equation (12). .

Therefore, the S parameter S ′ _{in_mla} in the case where power is supplied from the first port to the first antenna element 211 and the power supply voltage of the second antenna element 212 is 0 V is given by the equation (17) or the equation (18). the calculated input impedance _{Z'In_mla} can be calculated by the equation (19) follows using.

In the case where power is supplied from the second port to the second antenna element 212 and the power supply voltage of the first antenna element 211 is 0 V, the input impedance Z ′ _{in_ma} when the value of Z ₀₁ is 0 is It is calculated by the equation (20). Further, the input impedance Z ′ _{in_ma} when the value of Z ₀₁ is infinite is calculated by the following equation (21).

Equation (20) and (21) in the _{A'mla, B'mla, C'mla} , and _D'mla, the following as shown in equation (22), F parameter F _mla inverse matrix F _mla It is an element of ^-1 and a value that can be calculated.

Therefore, the S parameter S ′ _{in_mla} in the case where power is supplied from the second port to the second antenna element 212 and the power supply voltage of the first antenna element 211 is 0 V is given by Equation (20) or Equation (21). Using the calculated input impedance Z ′ in — _ma , it can be calculated by the above-described equation (19).

  As described above, the antenna characteristic calculation unit 133b simulates the S parameter of the antenna model with the matching circuit in consideration of the loss of the matching element including the parasitic reactance and the loss resistance, the loss of the line, and the interaction between the antenna elements. Get without depending on. That is, in the embodiment, the antenna characteristic calculation unit 133b calculates the S parameter of the antenna model with a matching circuit, the characteristics of an antenna including a plurality of antenna elements, the characteristics of each matching element constituting the matching circuit, and the characteristics of the line. Use to calculate by analytical method.

  Therefore, according to the embodiment, the antenna characteristics of the antenna model with a matching circuit that takes into account the loss of the matching element, the loss of the line, and the interaction between the antenna elements can be acquired in a short time, and the desired antenna can be obtained. Design can be performed efficiently.

Next, a method for calculating the radiation efficiency of the antenna model with a matching circuit according to the embodiment will be described.
P _nml1 shown in FIG. 3 is the net electric power sent from the wave source 330 and inputted to the first circuit 320-1.

P _na is the net electric power input to the antenna 310, and is represented by the relation P _na = P _nml1 −P _Lossml1, where P _Lossml1 is a loss due to mismatch in the first circuit.

P _rad is radiated power, and is represented by the relation P _rad = P _na −P _Lossa, where P _Lossa is the power lost due to the loss included in the antenna 210 such as dielectric loss and conductor loss.

P _Nml2 is the net power to be input to the second circuit 320-1, equation _P nml2 = P _na - represented by (P _Lossmla + P _rad).

P _Load2 is the power output to the second port, and is represented by the relation P _Load2 = P _nml2 −P _Lossml2 where P _Lossml2 is a loss due to mismatch in the second circuit.

I ₁ shown in FIG. 3 is a current flowing in a circuit after the wave source 330, and flows in the first circuit 320-1, the antenna 310, the second circuit 320-2, and the load on the second port side. Current. V ₁ is a voltage applied to a circuit after the wave source 330, and is a voltage applied to the first circuit 320-1, the antenna 310, the second circuit 320-2, and the load on the second port side. It is.

I _a is a current that flows in a circuit after the first circuit 320-1, and is a current that flows in the antenna 310, the second circuit 320-2, and the load on the second port side. V _a is a voltage applied to a circuit after the first circuit 320-1, and is a voltage applied to the antenna 310, the second circuit 320-2, and the load on the second port side.

I _ml2 is a current flowing through the circuit after the antenna 310, and is a current flowing through the second circuit 320-2 and the load on the second port side. V _ml2 is a voltage applied to the circuit after the antenna 310, and is a voltage applied to the second circuit 320-2 and the load on the second port side.

I ₂ is a current that flows through a circuit after the second circuit 320-2, and a current that flows through the load on the second port side. V ₂ is a voltage applied to a circuit after the second circuit 320-2, and is a voltage applied to the load on the second port side.

In the equivalent circuit 300 of the antenna model with a matching circuit, the radiation efficiency η can be calculated by the following equation (23).

P _na , P _nml2 , P _nml1 , and P _rad / (P _rad + P _Lossa ) in the equation (23) can be calculated as follows.
First, P _rad / (P _rad + P _Lossa ) in the equation (23) can be derived as follows using an equivalent circuit of the antenna 210 alone.

  FIG. 7 is an equivalent circuit diagram of an exemplary antenna unit model. In the equivalent circuit 500 of the single antenna model shown in FIG. 7, the same reference numerals are given to the same elements as those of the equivalent circuit 300 of the antenna model with a matching circuit.

In FIG. 7, the radiation efficiency η _a of the antenna 310 alone can be expressed as in the following formula (24).

Further, P _na can be expressed as in the following equation (25) using the F parameter F _a of the antenna 310 alone shown in equation (3).

Here, in the analysis of the antenna characteristics for the single antenna 210 model, Z ₀₁ = Z ₀₂ = Z ₀ is set. Further, since V ₂ = Z ₀₂ I ₂ , P _na can be further expressed as in the following formula (26).

Further, P _Load2 can be expressed as the following equation (27).

From the equations (26) and (27), the relationship between P _na and P _Load2 can be expressed as the following equation (28).

Therefore, P _rad / (P _rad + P _Lossa ) in the equation (23) can be expressed as the following equation (29) using the equations (24) and (28).

As described above, in the embodiment, η _a in the equation (29) is a known value. That is, the radiation efficiency η _a of the antenna 210 alone is acquired by simulation of the simulation execution unit 131b and stored in the antenna characteristic file 121 in some embodiments, and the radiation efficiency of the antenna 310 alone in some embodiments. η _a is acquired by input through the input unit 110. In the embodiment, α in equation (29) can be calculated by equation (28).
Therefore, P _rad / (P _rad + P _Lossa ) in the equation (23) can be calculated by the equation (29).

Next, P _nml2 in the equation (23) can be expressed as the following equation (30).

A _ml2 , B _ml2 , C _ml2 , and D _ml2 in equation (30) are elements of the F parameter F _ml2 of the second circuit 320-2 and can be calculated as described above while showing equation (11). It is. Further, in the antenna model 200 with a matching circuit, the reference impedance of the port that does not feed the antenna element may be the reference impedance Z ₀ or an arbitrary value Z ₀ ′. That is, in the example shown in FIG. 3, the reference impedance Z ₀₂ of the second port in the equation (30) is a known value given by an input through the input unit 110.

Further, P _na in the formula (23) can be expressed as the following formula (31).

A _aml2 , B _aml2 , C _aml2 and D _aml2 in the formula (31) are elements of the matrix _represented by the following formula (32).

As described above with equations (3) and (11), in embodiments, F _a and F _ml2 can be calculated. Thus, in an embodiment, A _mla2 , B _mla2 , C _mla2 and D _mla2 in formula (31) can be calculated. As described above, Z ₀₂ is a known value.

P _nml1 in the equation (23) can be expressed as the following equation (33).

As described above with reference to equation (12), in embodiments, A _mla , B _mla , C _mla , and D _mla in equation (31) can be calculated. Further, as described above, Z ₀₂ in the formula (31) is a known value.
As described above, P _rad / (P _rad + P _Lossa ), P _nml2 , P _na , and P _nml1 in the equation (23) are _expressed by the equations (29), (30), (31), and ( 33) respectively.

Here, in the embodiment, it is assumed that the value of P _rad / (P _rad + P _Lossa ) is unchanged between the model of the antenna 210 alone and the antenna model 200 with a matching circuit. When Expression (29), Expression (30), Expression (31), and Expression (33) are substituted into Expression (23), | I ₂ | ² is canceled during the calculation.
Therefore, the radiation efficiency η of the antenna model 200 with a matching circuit can be calculated by Expression (23).

As described above, in the antenna model 200 with a matching circuit, the reference impedance of the port that does not supply power to the antenna element may not be the reference impedance Z ₀ , and an arbitrary value can be given. That is, in the example shown in FIG. 3, the reference impedance Z ₀₂ of the second port can give any value from 0 to infinity (∞).

However, in the case where the second port is opened and Z ₀₂ is set to infinity, the equation (23) is obtained using the equations (30), (31), and (33). It is not possible to calculate P _nml2 , P _na , and P _nml1 .

Therefore, when Z ₀₂ is set to infinity, the above-described equations (30), (31), and (33) are changed to the following equations (34), (35), and (36): Respectively transformed into.

When Z ₀₂ is set to infinity, the radiation efficiency η of the antenna model 200 with a matching circuit is expressed by the following equation (29), (34), (35), and (36): It can be calculated as in 37).

  In the above description, as shown in FIG. 3, a method for calculating the radiation efficiency η in the case where the first antenna element 211 is fed from the first port and the feeding voltage of the second antenna element 212 is 0V is described. did. However, the radiation efficiency η in the case where power is supplied from the second port to the second antenna element 212 and the power supply voltage of the first antenna element 211 is 0 V can be calculated by the same method.

  As described above, the antenna characteristic calculation unit 133b calculates the radiation efficiency η of the antenna model with the matching circuit in consideration of the loss of the matching element including the parasitic reactance and the loss resistance, the loss of the line, and the interaction between the antenna elements. Acquire without simulation. That is, in the embodiment, the antenna characteristic calculation unit 133b determines the radiation efficiency η of the antenna model with a matching circuit, the characteristics of a single antenna including a plurality of antenna elements, the characteristics of each matching element constituting the matching circuit, and the characteristics of the line. To calculate by analytical method.

  Therefore, according to the embodiment, the antenna characteristics of the antenna model with a matching circuit that takes into account the loss of the matching element including the parasitic reactance and the loss resistance, the loss of the line, and the interaction between the antenna elements are acquired in a short time. Therefore, a desired antenna design can be performed efficiently.

Finally, a method for calculating the total efficiency of the antenna model with a matching circuit according to the embodiment will be described.
The total efficiency η _t of the antenna model with a matching circuit can be calculated by the following equation (38).

As described above shows the equation (13), in the embodiment, the reflection coefficient S ₁₁ in formula (38) can be calculated. In addition, as described above with Expression (23) and Expression (37), in the embodiment, the radiation efficiency η in Expression (38) can be calculated.
Therefore, the total efficiency η _t of the antenna model with a matching circuit can be calculated by Expression (38).

As described above, the antenna characteristic calculation unit 133b calculates the total efficiency η _{t of the} antenna model with the matching circuit in consideration of the loss of the matching element including the parasitic reactance and the loss resistance, the loss of the line, and the interaction between the antenna elements. Is obtained without simulation. That is, in the embodiment, the antenna characteristic calculation unit 133b calculates the total efficiency η _t of the antenna model with a matching circuit, the characteristics of a single antenna including a plurality of antenna elements, the characteristics of each matching element constituting the matching circuit, and the line Calculate by analytical method using characteristics.

  Therefore, according to the embodiment, the antenna characteristics of the antenna model with a matching circuit that takes into account the loss of the matching element, the loss of the line, and the interaction between the antenna elements can be acquired in a short time, and the desired antenna can be obtained. Design can be performed efficiently.

  In the above description, the calculation method of the antenna characteristic of the antenna model with the matching circuit in which the loss of the matching element, the loss of the line, and the interaction between the antenna elements is considered as an example of the calculation method of the antenna characteristic according to the embodiment. explained. However, the antenna characteristics of the antenna model with a matching circuit that takes into account the loss of the matching element and the interaction between the antenna elements can also be calculated by modifying the calculation method described above, such as omitting the calculation related to the line. It is clear that an effect similar to the effect can be obtained.

  It will be described below using a specific example that the antenna characteristic calculation method according to the embodiment has sufficient calculation accuracy to withstand practical use. In the following description, the antenna characteristic obtained by the calculation method according to the embodiment is compared with the antenna characteristic obtained by electromagnetic field simulation. The antenna characteristics by the electromagnetic field simulation can also be acquired by a computer according to any electromagnetic field simulation software such as Poynting (registered trademark).

  The specific example shown below is an example for explaining the calculation accuracy of the calculation method of the antenna characteristics of the embodiment. If the value of each parameter shown in the following specific example is not used, the calculation according to the embodiment is performed. It does not mean that the method cannot obtain calculation accuracy that can withstand practical use.

FIG. 8 is an explanatory diagram of an antenna model with a matching circuit used for verification of calculation accuracy.
An antenna model 600 with a matching circuit shown in FIG. 8 includes an antenna 610, a ground conductor 620, and a substrate 630.

  The antenna 610 is disposed on the upper surface of the substrate 630, and the ground conductor 620 is disposed on the lower surface of the substrate 630. There is no ground conductor 620 below the antenna 610 disposed on the upper surface of the substrate 630.

  The antenna 610 includes a first antenna element 611 and a second antenna element 612. The first antenna element 611 and the second antenna element 612 are linear antenna elements. The widths of the linear first antenna element 611 and the second antenna element 612 are each 1 mm.

  The linear first antenna element 611 is bent at a right angle, and the first straight line portion 611a on the port 1 side and the second straight line portion 611b on the opposite side to the port 1 side with the bending point as a boundary. Including. The length of the first straight line portion 611a is 10 mm, and the length of the second straight line portion 611b is 24 mm.

  The linear second antenna element 612 is bent at a right angle, and the third straight line portion 612a on the port 2 side and the fourth straight line on the opposite side to the port 2 side with the bending point as a boundary. Part 612b. The length of the third straight portion 612a is 10 mm, and the length of the fourth portion 612b is 11 mm.

  Thus, unlike the shape of the first antenna element 611 and the shape of the second antenna element 612, the shape of the antenna 610 is asymmetric.

  The ground conductor 620 is a metal plate having a rectangular surface (upper surface and lower surface). The length of the side of the surface of the ground conductor 620 parallel to the first straight line portion 611a and the third straight line portion 612a is 100 mm, and is parallel to the second straight line portion 611b and the fourth straight line portion 612b. The length of the side is 50 mm. The ground conductor 620 is considered a complete conductor.

  The substrate 630 is disposed between the antenna 610 and the ground conductor 620. The thickness of the substrate 630 is 1 mm. The relative dielectric constant of the substrate 630 is 4.0, and the dielectric loss is 0.02 at 2 GHz.

  Matching circuits are connected to the port 1 side of the first antenna element 611 and the port 2 side of the second antenna element 612, respectively.

  FIG. 9 is an equivalent circuit diagram of the antenna model with a matching circuit shown in FIG. In the equivalent circuit 700 of the antenna model with a matching circuit illustrated in FIG. 9, the antenna 710 corresponds to the antenna 610. The first matching circuit 720-1 corresponds to the matching circuit connected to the port 1 side of the first antenna element 611, and the second matching circuit 720-2 is the port 2 side of the second antenna element 612. Corresponds to the matching circuit connected to the.

  As shown in FIG. 9, the first matching circuit 720-1 includes an inductor connected in series with the first antenna element 611, and the inductance is 1.2 nH. The first matching circuit 720-1 includes a capacitor connected in parallel with the first antenna element 611, and the capacitance thereof is 2.5 nF. The second matching circuit 720-2 includes an inductor connected in series with the second antenna element 612, and its inductance is 4 nH. The second matching circuit 720-2 includes an inductor connected in parallel with the second antenna element 612, and the inductance is 1.6 nH.

First, as a first verification example, there is a matching circuit in the case where the reference impedance Z ₀₁ of the first port and the reference impedance Z ₀₂ of the second port are both 50Ω (Z ₀₁ = Z ₀₂ = Z ₀ = 50Ω) The antenna characteristics of the antenna model 600 will be described.

  The verification result of the S parameter in the first verification example will be described with reference to FIGS. 10 to 14 are verification results when power is supplied from the port 1 to the first antenna element 611 and the power supply voltage from the port 2 to the second antenna element 612 is 0V.

FIG. 10 is a frequency characteristic diagram of S ₁₁ in the first verification example. Figure 11 is a Smith chart of S ₁₁ in the first test example. As can be understood from FIGS. 10 and ₁₁ , the tendency of the transition of the reflection coefficient S ₁₁ of the port 1 at the measurement frequency of 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. For example, the frequency with the lowest value of the reflection coefficient S ₁₁ of the port 1 is about 2000 MHz in the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. In addition, the value of the reflection coefficient S ₁₁ of the port 1 at the measurement frequency 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment.

FIG. 12 is a frequency characteristic diagram of S ₂₂ in the first verification example. Figure 13 is a Smith chart of S ₂₂ in the first test example. As can be understood from FIGS. 12 and 13, the tendency of transition of the reflection coefficient S ₂₂ of the port 2 at the measurement frequency 1500~2500MHz approximately corresponds with the calculation method according to the simulation results of the embodiment by the electromagnetic field simulation. For example, the frequency with the lowest value of the reflection coefficient S ₂₂ of the port 2 is about 2000 MHz in the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. In addition, the value of the reflection coefficient S ₂₂ of the port 2 at the measurement frequency 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment.

FIG. 14 is a frequency characteristic diagram of S ₂₁ and S ₁₂ in the first verification example. As can be understood from FIG. 14, the transition tendency of the transfer coefficient S ₂₁ from port 1 to port 2 and the transfer coefficient S ₁₂ from port 2 to port 1 at a measurement frequency of 1500 to 2500 MHz is similar to the simulation result by electromagnetic field simulation. The calculation method according to the embodiment is almost the same. For example, the frequency with the highest values of the transfer coefficients S ₂₁ and S ₁₂ is about 2000 MHz, which is the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment.

  Thus, from the verification results shown in FIGS. 10 to 14, it can be understood that the calculation method of the embodiment is a calculation method having a calculation accuracy that can withstand practical use.

The verification results of the radiation efficiency and the total efficiency in the first verification example will be described with reference to FIGS.
FIG. 15 is a frequency characteristic diagram of the radiation efficiency of the first antenna element in the first verification example. FIG. 16 is a frequency characteristic diagram of the total efficiency of the first antenna element in the first verification example. The verification results shown in FIGS. 15 and 16 are verification results when power is supplied from the port 1 to the first antenna element 611 and the power supply voltage from the port 2 to the second antenna element 612 is 0V.

As can be understood from FIG. 15 and FIG. 16, the tendency of the transition of the radiation efficiency and the total efficiency of the first antenna element 611 at the measurement frequency 1500 to 2500 MHz depends on the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. Almost matches. Further, the radiation efficiency and the total efficiency of the first antenna element 611 at the measurement frequency of 1500 to 2500 MHz are almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. For example, as described above in the description of the equation (23), in the calculation of the radiation efficiency according to the embodiment, the value of P _rad / (P _rad + P _Lossa ) is calculated for the antenna model and the antenna model with a matching circuit. Pretends to be immutable. From the verification examples of FIGS. 15 and 16, it can be understood that the calculation method of the embodiment using such a fake is a calculation method having a calculation accuracy that can withstand practical use.

  FIG. 17 is a frequency characteristic diagram of the radiation efficiency of the second antenna element in the first verification example. FIG. 18 is a frequency characteristic diagram of the total efficiency of the second antenna element in the first verification example. The verification results shown in FIGS. 17 and 18 are verification results when power is supplied from the port 2 to the second antenna element 612 and the power supply voltage from the port 1 to the first antenna element 611 is 0V.

  As can be understood from FIGS. 17 and 18, the tendency of the transition of the radiation efficiency and the total efficiency of the second antenna element 612 at the measurement frequency of 1500 to 2500 MHz depends on the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. Almost matches. In addition, the radiation efficiency and the total efficiency of the second antenna element 612 at the measurement frequency of 1500 to 2500 MHz are almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. From the verification examples of FIGS. 17 and 18, it can be understood that the calculation method of the embodiment using the above-described fake is a calculation method having a calculation accuracy that can withstand practical use.

Next, as a second verification example, the reference impedance Z ₀₁ of the first port is set to 50Ω (Z ₀₁ = Z ₀ = 50Ω), and the reference impedance Z ₀₂ of the second port is set to a value other than 50Ω (Z ₀₂ ≠ The antenna characteristics of the antenna model 600 with a matching circuit in the case of Z ₀ ) will be described.

The verification result of the S parameter in the second verification example will be described with reference to FIGS. The verification results of FIGS. 19 to 22 are verification results when power is supplied from the port 1 to the first antenna element 611 and the power supply voltage from the port 2 to the second antenna element 612 is 0V. Further, the verification results of FIGS. 19 and 20 are verification results when the reference impedance Z ₀₂ of the second port is 0. The verification results of FIGS. 21 and 22 are verification results when the reference impedance Z ₀₂ of the second port is infinite.

FIG. 19 is a frequency characteristic diagram of S ₁₁ in the case where the reference impedance Z ₀₂ of the second port is 0. As can be understood from FIG. 19, the transition tendency of the reflection coefficient S ₁₁ of the port 1 at the measurement frequency of 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. For example, the frequency at which the value of the reflection coefficient S ₁₁ of port 1 is the lowest is about 2100 MHz in the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. In addition, the value of the reflection coefficient S ₁₁ of the port 1 at the measurement frequency 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment.

FIG. 20 is a frequency characteristic diagram of the total efficiency of the first antenna element in the case where the reference impedance Z ₀₂ of the second port is 0.
As can be understood from FIG. 20, the tendency of transition of the total efficiency of the first antenna element 611 at the measurement frequency of 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. In addition, the value of the total efficiency of the first antenna element 611 at the measurement frequency of 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment.

FIG. 21 is a frequency characteristic diagram of S ₁₁ in the case where the reference impedance Z ₀₂ of the second port is infinite. As can be understood from FIG. 21, the tendency of transition of the reflection coefficient S ₁₁ of the port 1 at the measurement frequency 1500~2500MHz approximately corresponds with the calculation method according to the simulation results of the embodiment by the electromagnetic field simulation. For example, the frequency with the lowest value of the reflection coefficient S ₁₁ of the port 1 is about 2000 MHz in the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. In addition, the value of the reflection coefficient S ₁₁ of the port 1 at the measurement frequency 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment.

FIG. 22 is a frequency characteristic diagram of the total efficiency of the first antenna element in the case where the reference impedance Z ₀₂ of the second port is infinite.
As can be understood from FIG. 22, the tendency of transition of the total efficiency of the first antenna element 611 at the measurement frequency of 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment. In addition, the value of the total efficiency of the first antenna element 611 at the measurement frequency of 1500 to 2500 MHz is almost the same between the simulation result by the electromagnetic field simulation and the calculation method according to the embodiment.

  From the verification results shown in FIGS. 19 and 21 as described above, even when the reference impedance of the port of the antenna element that is not fed is set to an arbitrary value, the calculation accuracy with which the calculation method of the embodiment can withstand practical use is obtained. It can be understood that the calculation method has Further, from the verification results shown in FIG. 20 and FIG. 22, even when the reference impedance of the port of the antenna element that is not fed is set to an arbitrary value, the calculation method of the embodiment using the above-described pseudo control is as follows. It can be understood that this calculation method has a calculation accuracy that can withstand practical use.

From the verification results of the first and second verification examples described above, it can be understood that the calculation method of the embodiment is a calculation method having a calculation accuracy that can withstand practical use.
An example of an antenna design processing flow according to the embodiment will be described below.

FIG. 23 is an example diagram of an antenna design processing flow according to the embodiment.
In the antenna design processing flow shown in FIG. 23, the antenna design apparatus 100 executes antenna design in consideration of the loss of the line between the antenna and the wave source in addition to the interaction between the antenna elements and the loss of the matching element. It is an example of the processing flow of a case to do. In the case of the antenna design processing flow shown in FIG. 23, except for the process related to the line design, the antenna design apparatus 100 executes the antenna design considering only the interaction between the antenna elements and the loss of the matching element. This is an example of a processing flow.

  In step 101, the antenna model creation unit 131a without a matching circuit creates a model of a single antenna according to the model condition data input via the input unit 110. The antenna model creation unit 131a without a matching circuit creates a model including an antenna and a line according to the model condition data input via the input unit 110. The antenna created by the antenna model creation unit 131a without a matching circuit includes a plurality of antenna elements. As described above, the model condition data input via the input unit 110 includes data on the model shape, model material, wave source, circuit components, analysis conditions, and analysis output items.

  The line model creation unit 132 a creates a line model according to the model condition data input via the input unit 110.

  In step 102, the simulation execution unit 131b performs a simulation on the single antenna model created by the antenna model creation unit 131a without a matching circuit, and acquires antenna characteristics. Moreover, the simulation execution part 131b performs a simulation with respect to the model containing the antenna and the line | wire produced by the antenna model creation part 131a without a matching circuit, and acquires an antenna characteristic.

  Specifically, the simulation execution unit 131b obtains the antenna characteristics of Case 1 by feeding power to the first antenna element included in the antenna and setting the feeding voltage of the second antenna element to 0 V by simulation. In addition, the simulation execution unit 131b supplies power to the second antenna element included in the antenna, and acquires the antenna characteristics of case 2 in which the power supply voltage of the first antenna element is 0 V by simulation.

  In the simulation by the simulation execution unit 131b, the reference impedance of the port that is not supplied with power to the antenna element may be any set value input via the input unit 110.

  In addition, as described above with Expression (14) and Expression (29), etc., in the antenna characteristic calculation processing of the antenna model with a matching circuit according to the embodiment, the reference impedance of the port of the antenna element that is not fed is used. And the antenna characteristic of the case where the reference impedance of the port of the fed antenna element has the same value. Therefore, for use in such calculation processing, the simulation execution unit 131b also executes a simulation of a case where the reference impedance of the port of the antenna element that is not fed and the reference impedance of the port of the fed antenna element are the same value. To do.

  The antenna characteristics acquired by the simulation execution unit 131b include impedance, S parameter, radiation efficiency, and total efficiency for each frequency set by the input of the input unit 110. The antenna characteristics of cases 1 and 2 with respect to the model of the single antenna acquired by the simulation execution unit 131b are stored in the antenna characteristic file 121, respectively.

  The line characteristic calculation unit 132b calculates line characteristics using the line model created by the line model creation unit 132a. The calculated line characteristics include a line impedance and a transfer coefficient (attenuation constant and phase constant) for each frequency set by the input of the input unit 110. The line characteristics calculated by the line characteristic calculation unit 132 b are stored in the line characteristic file 122.

  In step 103 to step 111, repeated processing is performed for each antenna element included in the antenna.

Specifically, in step 104, the simulation result determination unit 131c determines that the total efficiency η _t of the first antenna element (i = 1) of the model including the antenna and the line acquired by the simulation execution unit 131b is a desired standard. It is determined whether or not it is greater than or equal to the value. That is, the simulation result determination unit 131c determines whether or not the total efficiency η _t of the first antenna element in Case 1 is equal to or greater than a desired standard value.

If it is determined in step 104 that the total efficiency η _t is greater than or equal to the desired standard value (“NO” in step 104), the antenna design process proceeds to step 111.
If it is determined in step 104 that the total efficiency η _t is less than the desired standard value (“YES” in step 104), the antenna design process proceeds to step 105.

  In step 105, the display unit 140 displays a tool screen for designing an antenna model including a matching circuit.

FIG. 24 is an example of a display screen of the antenna model design tool with a matching circuit.
As shown in FIG. 24, the display screen 800 includes an area 810 for displaying the file name of the antenna characteristic file 121 and an area 820 for displaying the characteristics of the matching element added to the model including the antenna and the line. The display screen 800 includes an area 830 for displaying a calculation result for the antenna model with a matching circuit including the added matching element.

  When the file name of the antenna characteristic file 121 for each antenna element included in the antenna is input via the input unit 110, the file name of the input antenna characteristic file for each antenna element is displayed in the area 810. The antenna model creation unit with matching circuit 133a imports the antenna impedance, S parameter, and radiation efficiency for each frequency stored in the input antenna characteristic file 121.

  Depending on the embodiment, antenna characteristics for each antenna element are individually input via the input unit 110. The input antenna characteristics are displayed in area 810, respectively. The antenna model creation unit 133a with a matching circuit imports individually input antenna characteristics.

  In some embodiments, the antenna model creation unit with matching circuit 133a calculates a desired circuit configuration of the matching circuit connected to each antenna element based on the S parameter of the imported antenna model. In addition, the antenna model creation unit 133a with a matching circuit acquires circuit configuration data of each matching circuit that is input via the input unit 110 in some embodiments. The circuit configuration of each matching circuit calculated or obtained by the antenna model creation unit with matching circuit 133a may be configured to be displayed on the tool screen by the display unit 140.

  The matching circuit-equipped antenna model creation unit 133a determines matching elements that constitute each matching circuit that conforms to the use conditions in accordance with the calculated or acquired circuit configuration. The use conditions of the matching element are acquired in advance by the antenna model creation unit 133a with a matching circuit by an input via the input unit 110.

  Depending on the embodiment, characteristics of matching elements constituting each matching circuit are input via the input unit 110, and the characteristics of the input matching elements are displayed in the region 820. For example, when the matching element is a capacitor, an electrostatic capacity, an equivalent series inductance (ESR), and an equivalent series resistance (ESL) are input, and these input characteristics are input to the region 820. Is displayed. When the matching element is an inductor, an inductance, an accompanying capacitance, and an accompanying resistance are inputted, and these inputted characteristics are displayed in a region 820. The matching circuit-equipped antenna model creation unit 133a determines the matching element input via the input unit 110 as a matching element that meets the usage conditions.

  In some embodiments, the matching circuit-equipped antenna model creation unit 133a refers to matching element data stored in the matching element data file 124 to determine a matching element that meets the usage conditions.

  When the type of the matching element is a capacitor, the matching element data file 124 includes data on the matching element name, manufacturer name, size, capacitance, equivalent series inductance, equivalent series resistance, withstand voltage, and price.

  In addition to the capacitance, the capacitor includes an equivalent series resistance that is a loss resistance component and an equivalent series inductance that is a parasitic reactance component. In the embodiment, the antenna characteristics of the antenna model with a matching circuit are calculated in consideration of the equivalent series inductance and the equivalent series resistance in addition to the capacitance of the capacitor. Therefore, data regarding the equivalent series inductance and equivalent series resistance is stored in the matching element data file 124.

  When the type of the matching element is an inductor, the matching element data file includes data on the matching element name, manufacturer name, size, inductance, accompanying capacitance, accompanying resistance, withstand voltage, and price.

  In addition to the inductance, the inductor includes an accompanying resistance that is a loss resistance component and an accompanying capacitance that is a parasitic reactance component. In the embodiment, the antenna characteristics of the antenna model with a matching circuit are calculated by taking into account the accompanying capacitance and the accompanying resistance in addition to the inductance of the inductor. Therefore, data relating to the accompanying capacitance and the accompanying resistance is stored in the matching element data file 124.

  When determining a matching element that matches a use condition with reference to the matching element data file, the antenna model creation unit 133a with a matching circuit firstly uses the matching element data file 124 in ascending order or descending order for capacitance or inductance. Rearrange. Further, when there are matching elements having the same capacitance or inductance, the antenna model creation unit with matching circuit 133a sorts the prices of the matching elements in ascending or descending order. Then, the antenna model creation unit 133a with a matching circuit selects a matching element whose size and breakdown voltage match the matching element usage conditions from the matching element data file 124. When matching elements having the same size and breakdown voltage exist in the matching element data file 124, the antenna model creation unit 133a with a matching circuit selects a matching element having a small price value.

  When the matching element constituting each matching circuit is determined by the antenna model creation unit 133a with a matching circuit, the type of the determined matching element, capacitance or inductance, loss resistance, and parasitic reactance are displayed in the area 820. .

  In some embodiments, when the matching circuit calculated or obtained by the antenna model creation unit 133a with a matching circuit is a circuit in which matching elements are mounted in parallel to the antenna, the display unit 140 is parallel to the antenna. The display prompts the user to input the values of the via length h and the via diameter D connected to the matching element mounted on the board.

  Each value of the via length h and the via diameter D connected to the matching element mounted in parallel to the antenna is input via the input unit 110. The antenna characteristic calculation unit 133b calculates the inductance of the via using each value of the input via length h and the via diameter D. The calculated via inductance is added to the reactance of the matching element connected to the via.

  The antenna model creation unit 133a with a matching circuit imports the line impedance, attenuation constant, and phase constant for each frequency stored in the line characteristic file 122.

  The length of each line connected to each antenna element is input via the input unit 110. Depending on the embodiment, the characteristic impedance, attenuation constant α, and phase constant β of the line for each frequency are input via the input unit 110. In some embodiments, the antenna model creation unit 133a with a matching circuit imports the characteristic impedance, attenuation constant, and phase constant of the line for each frequency stored in the line characteristic file 122.

In step 106, the antenna characteristic calculation unit 133b calculates the antenna characteristic of the antenna model created by the antenna model creation unit 133a with a matching circuit according to the calculation method described above with reference to FIGS. The calculated antenna characteristics include S parameter, radiation efficiency η, and total efficiency η _t . The calculation result by the antenna characteristic calculation unit 133 b is stored in the calculation processing data file 123.

  The antenna characteristic calculator 133b calculates the power consumption of each of the line and the matching element included in the antenna model with a matching circuit. The calculation result by the antenna characteristic calculation unit 133 b is stored in the calculation processing data file 123.

As shown in FIG. 24, the S parameter, the radiation efficiency η, and the total efficiency η _t of the antenna model with a matching circuit calculated by the antenna characteristic calculation unit 133b are displayed in the area 830 of the display screen 800 by the display unit 140. .

In step 107, the calculation result determination unit 133c determines whether or not the total efficiency η _t calculated by the antenna characteristic calculation unit 133b is equal to or greater than a desired standard value.

When it is determined in step 107 that the total efficiency η _t is greater than or equal to a desired standard value (“NO” in step 107), the antenna design process proceeds to step 111.
If it is determined in step 107 that the total efficiency η _t is less than the desired standard value (“YES” in step 107), the antenna design process proceeds to step 108.

  In step 108, the calculation result determination unit 133c causes the display unit 140 to display the power consumption of the matching elements constituting each matching circuit, which is stored in the calculation processing data file 123. Depending on the embodiment, the calculation result determination unit 133c causes the printing device (not shown) connected to the antenna design device 100 to print the power consumption of the matching elements constituting each matching circuit.

  Further, in step 108, processing for exchanging matching elements constituting each matching circuit is executed. Details of the matching element replacement process in step 108 are shown in FIG.

FIG. 25 is an example of a matching element exchange process flow.
In step 201, the calculation result determination unit 133c sorts n matching elements (n is an integer of 1 or more) of all matching circuits in descending order of power consumption, and matches the sorted matching elements from 1 to n. Assign element numbers in ascending order. In addition, the calculation result determination unit 133c sets the count value j of the matching element number to 1.

  In step 202, the calculation result determination unit 133c has the same capacitance or inductance as the matching element having the same j-th matching element number as the count value j, and has a loss resistance higher than that of the matching element having the j-th matching element number. Search for a small matching element. Depending on the embodiment, the calculation result determination unit 133c searches the matching element data file 124 for a matching element.

  If there is a matching element in step 202 (“YES” in step 202), the process proceeds to step 203.

  In step 203, the antenna model creation unit 133a with a matching circuit replaces the matching element having the j-th matching element number included in the matching circuit with the matching element searched by the calculation result determination unit 133c.

  In step 204, the antenna characteristic calculation unit 133b calculates the antenna characteristic of the antenna model including the matching circuit in which the matching elements are replaced by the antenna model creation unit 133a with a matching circuit by the calculation method according to the above-described embodiment.

In step 205, the calculation result determination unit 133c determines whether or not the total efficiency η _{t of the} antenna model including the matching circuit in which the matching elements are replaced is equal to or higher than a desired standard value.

If it is determined in step 205 that the total efficiency η _t is equal to or greater than the desired standard value (NO in step 205), the antenna design process proceeds to step 111 in FIG.
If it is determined in step 205 that the total efficiency η _t is less than the desired standard value (“YES” in step 205), the antenna design process proceeds to step 206.

  If there is no corresponding matching element in step 202 (“NO” in step 202), the antenna design process proceeds to step 206.

  In step 206, the calculation result determination unit 133c increments the count value j by one. Then, in step 207, it is determined whether or not the count value j is less than or equal to the number n of matching elements in all matching circuits.

If it is determined in step 207 that the count value j is less than or equal to the number n of matching elements constituting the matching circuit (“YES” in step 207), the process returns to step 203 and the antenna design process is continued.
If it is determined in step 207 that the count value j exceeds the number n of matching elements constituting the matching circuit (“NO” in step 207), the antenna design process proceeds to step 109 in FIG.

  In step 109 of FIG. 23, the calculation result determination unit 133 c causes the display unit 140 to display a display prompting input of whether or not the track length can be changed. Then, the calculation result determination unit 133c determines whether or not the line length of the line included in the antenna model with a matching circuit can be changed according to whether or not the line length of the line input via the input unit 110 can be changed.

If the line length of the line is not changeable in step 109 (“NO” in step 109), the antenna design process proceeds to step 112.
If the line length of the line can be changed in step 109 (“YES” in step 109), the antenna design process proceeds to step 110.

  In step 110, the calculation result determination unit 133c causes the display unit 140 to display the power consumption of each line constituting the antenna model with a matching circuit stored in the calculation processing data file 123. Depending on the embodiment, the calculation result determination unit 133c causes the printing device (not shown) connected to the antenna design device 100 to print the power consumption of each line constituting the antenna model with a matching circuit.

  In step 110, a process of changing the line length of each line constituting the antenna model with a matching circuit is executed. The details of the process of changing the line length of the line at step 110 are shown in FIG.

FIG. 26 is an example of a process flow for changing the line length of the line.
In step 301, the calculation result determination unit 133c rearranges m (m is an integer of 1 or more) lines constituting the antenna model with a matching circuit in descending order of power consumption, and sets 1 to m on the rearranged lines. Assign track numbers in ascending order. In addition, the calculation result determination unit 133c sets the count value k of the line number to 1.

  In step 302, the calculation result determination unit 133c shortens the line length of the line having the same line number as the count value k. The length of the line length changed by the calculation result determination unit 133c is, for example, a length in which circuit elements connected by the line do not contact each other.

  In step 303, the calculation result determination unit 133c determines whether or not the circuit element connected to the line needs to be changed in accordance with the phase change of the impedance of the line due to the shortening of the line length.

If it is determined in step 303 that there is no need to change the circuit element (“YES” in step 303), the antenna design process proceeds to step 305.
If it is determined in step 303 that the circuit element needs to be changed (“NO” in step 303), the antenna design process proceeds to step 304.

  In step 304, a circuit element changing process is executed. The circuit element changing process executed in step 304 is, for example, a calculation process of the circuit configuration of the matching circuit and a matching element selection process by the above-described matching circuit-equipped antenna model creation unit 133a.

  In step 305, the matching-circuit-equipped antenna model creation unit 133 a re-creates the matching-circuit-equipped antenna model in which the line length is changed based on the change in the line length in step 302 and the change in the circuit element in step 304. The antenna characteristic calculation unit 133b calculates the antenna characteristics of the antenna model recreated by the antenna model creation unit 133a with a matching circuit according to the calculation method described above with reference to FIGS.

In step 306, the calculation result determination unit 133c determines whether or not the total efficiency η _{t of the} antenna model with a matching circuit whose line length is changed is equal to or greater than a desired standard value.
If it is determined in step 306 that the total efficiency η _t is greater than or equal to the desired standard value (“NO” in step 306), the antenna design process proceeds to step 111 in FIG.

If it is determined in step 306 that the total efficiency η _t is less than the desired standard value (“YES” in step 306), the antenna design process proceeds to step 307.

  In step 307, the calculation result determination unit 133c increments the count value k by one. In step 308, it is determined whether or not the count value k is equal to or less than the number m of lines forming the antenna model with a matching circuit.

If it is determined in step 308 that the count value k is equal to or less than the number of lines m (“YES” in step 308), the process returns to step 302 and the antenna design process is continued.
When it is determined in step 308 that the count value j exceeds the number m of lines (“NO” in step 308), the antenna design process proceeds to step 112 in FIG.

  In step 111 in FIG. 23, the count value i of the antenna element is incremented by one. Then, the repetition process of step 104 to step 110 is executed for the second antenna element (i = 2).

  When the iterative process for the second antenna element (i = 2) is executed, the process proceeds to step 112, and the antenna design process ends.

  If it is determined for all antenna elements that the total efficiency is equal to or greater than the standard value during the repetition process of step 103 to step 111 and the process proceeds to step 112, the antenna model created by the antenna model creation unit 133a with a matching circuit is created. Based on the above, the prototype or manufacture of the antenna is performed.

  On the other hand, when the process proceeds to step 112 after the process of step 109 and when the process proceeds to step 112 after the process of step 308, the basics such as the size and position of the antenna model that is returned to step 101 and input by the input unit 110 depending on the embodiment. The design condition data is changed, and the antenna design process according to the embodiment is performed again. Also, depending on the embodiment, the process returns to step 105, the use conditions of the matching element such as the size of the matching element are changed, and the antenna design process according to the embodiment is performed again.

  Note that the antenna design processing flow described above with reference to FIGS. 23 to 26 is merely an example, and the embodiment is not intended to be limited thereto. For example, the following changes can be added to the above-described antenna design processing flow.

  First, in step 101 of the antenna design processing flow, the input unit 110 inputs data related to the circuit configuration of the matching circuit, in addition to the various data described above, as the antenna model condition data.

  In step 105, the antenna model creation unit 133a with a matching circuit generates a matching circuit model including matching elements that do not include the parasitic reactance component and the loss resistance component according to the data regarding the circuit configuration of the matching circuit input by the input unit 110. create. Then, the antenna model creation unit 133a with a matching circuit causes the simulation execution unit 131b to execute a simulation for the created antenna model with a matching circuit, and acquires an optimum circuit constant.

  The antenna model creation unit 133a with a matching circuit determines matching elements constituting the matching circuit in accordance with the circuit constant acquired by the simulation execution unit 131b. Depending on the embodiment, the antenna model creation unit 133a with a matching circuit determines a matching element with reference to the matching element data file. In some embodiments, the antenna model creation unit 133a with a matching circuit determines a matching element based on matching element data input via the input unit 110.

  In step 106, the antenna characteristic calculation unit 133b calculates the antenna characteristic of the antenna model including the matching circuit constituted by the matching elements determined by the antenna model creation unit 133a with a matching circuit by the calculation method according to the above-described embodiment. To do.

  In the above-described embodiment, the antenna design method executed by the antenna design apparatus 100 has been described. However, the configuration and processing functions of the antenna design apparatus 100 described above can also be realized by software called an antenna design program. Therefore, the same antenna design process as the antenna design process executed by the antenna design apparatus 100 can be realized by a computer that executes the antenna design program.

FIG. 27 is a hardware configuration diagram of a computer that executes an antenna design program according to the embodiment.
As shown in FIG. 27, a computer 900 includes an input device 901, a reading device 902, a communication interface 903, a hard disk (HDD) 904, a central processing unit (CPU) 905, a random access memory (RAM) 906, a read only memory ( ROM) 907, a display device 908, and a bus 909 are included. Devices 901 to 908 included in the computer 900 are connected to each other by a bus 909.

  The input device 901 is a device that detects an operation performed by a user of the computer 900, and is, for example, a mouse and a keyboard.

  The reading device 902 is a device that reads a program and data contained in a variable recording medium such as a magnetic disk, an optical disk, and a magneto-optical disk, and is, for example, a Compact Disc / Digital Versatile Disc (CD / DVD) drive. The communication interface 903 is an interface for connecting the computer 900 to a communication network such as a local area network (LAN). The HDD 904 is a storage device that stores programs executed by the CPU 905 and data.

  The antenna design program according to the embodiment is installed in the HDD 904 when the reading device 902 reads the antenna design program recorded on the variable recording medium. Alternatively, the antenna design program according to the embodiment is installed in the HDD 904 when the computer 900 acquires the antenna design program stored in another computer device (not shown) via the communication interface 903.

  The CPU 905 is a processing device that executes the antenna design process according to the embodiment by reading the antenna design program from the HDD 904 to the RAM 906 and executing the antenna design program.

  The RAM 906 is a memory that stores the execution result of the antenna design program read from the HDD 904. The ROM 907 is a read-only memory that stores constant data and the like.

  The display device 908 is a device that displays the processing result of the CPU 905 and the like, for example, a liquid crystal display device.

  As described above, the antenna characteristics including the loss of the matching element and the interaction between the antenna elements are calculated by an analytical method using the characteristics of the antenna alone and the characteristics of the matching element. In addition to the matching element loss and the interaction between antenna elements, the antenna characteristics including the line loss are calculated by an analytical method using the characteristics of the antenna alone, the matching element characteristics, and the line characteristics. Is done.

  Therefore, according to the antenna characteristic calculation method according to the embodiment, the antenna characteristic including the interaction between the antenna elements and the loss of the circuit element as described above can be obtained in a short time compared to the case of obtaining by simulation. The desired antenna design can be performed quickly and efficiently.

  In the embodiment, the circuit elements included in the antenna model are subjected to the antenna design process so that the total efficiency of the antenna model that takes into account the loss of the matching element and the interaction between the antenna elements satisfies a desired standard value. It is changed appropriately. In the embodiment, the circuit elements included in the antenna model satisfy the desired standard value so that the total efficiency of the antenna model including the loss of the matching element, the loss of the line, and the interaction between the antenna elements satisfies a desired standard value. It is changed as appropriate during the antenna design process.

  Therefore, according to the antenna characteristic calculation method according to the embodiment, it is possible to efficiently perform the antenna design process in consideration of the interaction between the antenna elements and the loss of the circuit elements as described above.

Regarding the above embodiment, the following additional notes are disclosed.
(Appendix 1)
Creating an antenna model including an antenna including a plurality of antenna elements and a matching circuit connected to each of the plurality of antenna elements, the matching circuit including a matching element including a parasitic reactance and a loss resistance;
Obtaining the characteristics of the antenna and the matching element;
Calculate the characteristics of the created antenna model using the acquired characteristics of the antenna and the characteristics of the matching element,
Determining whether the calculated characteristics of the antenna model satisfy a desired standard value;
An antenna design method in which a computer executes a process of displaying a determined result.
(Appendix 2)
The antenna characteristic includes an S parameter of the antenna, the matching element characteristic includes an impedance of the matching element, the antenna model characteristic includes an S parameter of the antenna model,
The computer calculates the F parameter of the antenna using the S parameter of the antenna, calculates the F parameter of the matching circuit using the impedance of the matching element, and calculates the calculated F parameter of the antenna and the matching The antenna design method according to appendix 1, wherein an S parameter of the antenna model is calculated using an F parameter of a circuit.
(Appendix 3)
The characteristics of the antenna model include the total efficiency of the antenna model,
The computer assumes that the ratio of the radiation efficiency of the antenna and the sum of the loss of the antenna and the radiation efficiency is the same for the model of the antenna alone and the antenna model, and the total efficiency of the antenna model The antenna design method according to attachment 2, wherein:
(Appendix 4)
When the matching element is mounted in parallel to the antenna, the computer calculates the inductance of the via connected to the matching element, and uses the calculated via inductance to determine the characteristics of the antenna model. The antenna design method according to any one of appendices 1 to 3, which is calculated.
(Appendix 5)
The antenna according to any one of appendices 1 to 4, wherein the computer selects the matching element that constitutes the matching circuit by referring to a matching element data file that includes data relating to a use condition of the matching element. Design method.
(Appendix 6)
The antenna design method according to any one of appendices 1 to 5, wherein when the computer determines that the characteristics of the antenna model do not satisfy the desired standard value, the computer displays power consumption of the matching element. .
(Appendix 7)
The computer
In addition to the antenna and the matching circuit, create an antenna model including lines connected to the plurality of antenna elements,
Get the characteristics of the line,
The characteristics of the created antenna model are calculated using the characteristics of the line in addition to the characteristics of the antenna and the characteristics of the matching element.
The antenna design method according to attachment 1.
(Appendix 8)
Matching for creating an antenna model including an antenna including a plurality of antenna elements and a matching circuit connected to each of the plurality of antenna elements, the matching circuit including a parasitic reactance and a loss resistance An antenna model generator with a circuit;
The characteristics of the antenna and the characteristics of the matching element are acquired, and the characteristics of the antenna model created by the antenna model creation unit with the matching circuit are calculated using the acquired characteristics of the antenna and the characteristics of the matching element. An antenna characteristic calculator,
A calculation result determination unit that determines whether or not the characteristics of the antenna model calculated by the antenna characteristic calculation unit satisfy a desired standard value;
A display unit for displaying a result determined by the calculation result determination unit;
Antenna design apparatus including
(Appendix 9)
The antenna characteristic includes an S parameter of the antenna, the matching element characteristic includes an impedance of the matching element, the antenna model characteristic includes an S parameter of the antenna model,
The antenna characteristic calculation unit calculates an F parameter of the antenna using an S parameter of the antenna, calculates an F parameter of the matching circuit using an impedance of the matching element, and calculates the calculated F parameter of the antenna. The antenna design device according to appendix 8, wherein an S parameter of the antenna model is calculated using an F parameter of the matching circuit.
(Appendix 10)
The characteristics of the antenna model include the total efficiency of the antenna model,
The antenna characteristic calculation unit assumes that the ratio of the radiation efficiency of the antenna and the sum of the loss of the antenna and the radiation efficiency is the same between the model of the antenna alone and the antenna model, and The antenna design apparatus according to appendix 9, wherein the total efficiency is calculated.
(Appendix 11)
When the matching element is mounted in parallel with the antenna, the antenna characteristic calculation unit calculates an inductance of a via connected to the matching element, and uses the calculated inductance of the via to calculate the antenna model. The antenna design device according to any one of appendices 8 to 10, which calculates the characteristics of
(Appendix 12)
The antenna model creation unit with a matching circuit selects any one of the matching elements constituting the matching circuit by referring to a matching element data file including data relating to use conditions of the matching elements. The antenna design device according to one item.
(Appendix 13)
If the calculation result determination unit determines that the characteristics of the antenna model do not satisfy the desired standard value, the calculation result determination unit displays the power consumption of the matching element on the display unit. The antenna design device according to one item.
(Appendix 14)
In addition to the antenna and the matching circuit, the antenna model creating unit with a matching circuit creates an antenna model including lines connected to the plurality of antenna elements,
The antenna characteristic calculation unit obtains the characteristics of the line, and calculates the characteristics of the created antenna model using the characteristics of the line in addition to the characteristics of the antenna and the characteristics of the matching element,
The antenna design device according to appendix 8.
(Appendix 15)
Creating an antenna model including an antenna including a plurality of antenna elements and a matching circuit connected to each of the plurality of antenna elements, the matching circuit including a matching element including a parasitic reactance and a loss resistance;
Obtaining the characteristics of the antenna and the matching element;
Calculate the characteristics of the created antenna model using the acquired characteristics of the antenna and the characteristics of the matching element,
Determining whether the calculated characteristics of the antenna model satisfy a desired standard value;
An antenna design program for causing a computer to execute a process for displaying a determined result.
(Appendix 16)
The antenna characteristic includes an S parameter of the antenna, the matching element characteristic includes an impedance of the matching element, the antenna model characteristic includes an S parameter of the antenna model,
The computer calculates the F parameter of the antenna using the S parameter of the antenna, calculates the F parameter of the matching circuit using the impedance of the matching element, and calculates the calculated F parameter of the antenna and the matching The antenna design program according to appendix 15, wherein an S parameter of the antenna model is calculated using an F parameter of a circuit.
(Appendix 17)
The characteristics of the antenna model include the total efficiency of the antenna model,
The computer assumes that the ratio of the radiation efficiency of the antenna and the sum of the loss of the antenna and the radiation efficiency is the same for the model of the antenna alone and the antenna model, and the total efficiency of the antenna model The antenna design program according to appendix 16, which calculates
(Appendix 18)
When the matching element is mounted in parallel to the antenna, the computer calculates the inductance of the via connected to the matching element, and uses the calculated via inductance to determine the characteristics of the antenna model. The antenna design program according to any one of appendices 15 to 17, which is calculated.
(Appendix 19)
The antenna according to any one of appendices 15 to 18, wherein the computer selects the matching element that constitutes the matching circuit by referring to a matching element data file including data relating to use conditions of the matching element. Design program.
(Appendix 20)
The antenna design program according to any one of appendices 15 to 19, wherein when the computer determines that the characteristics of the antenna model do not satisfy the desired standard value, the computer displays the power consumption of the matching element. .
(Appendix 21)
The computer
In addition to the antenna and the matching circuit, create an antenna model including lines connected to the plurality of antenna elements,
Get the characteristics of the line,
The characteristics of the created antenna model are calculated using the characteristics of the line in addition to the characteristics of the antenna and the characteristics of the matching element.
The antenna design program according to attachment 15.

DESCRIPTION OF SYMBOLS 100 Antenna design apparatus 110 Input part 120 Storage part 121 Antenna characteristic file 122 Line characteristic file 123 Calculation processing data file 124 Matching element data file 130 Processing part 131 Antenna characteristic simulation processing part 131a No matching circuit antenna model creation part 131b Simulation execution part 131c Simulation result determination unit 132 Line characteristic calculation processing unit 132a Line model creation unit 132b Line characteristic calculation unit 133 Antenna characteristic calculation processing unit 133a Antenna model creation unit with matching circuit 133b Antenna characteristic calculation unit 133c Calculation result determination unit 140 Display unit 200, 600 Antenna model with matching circuit 210, 610 Antenna 211, 611 First antenna element 611a First linear portion 611b Second Linear portion 212, 612 Second antenna element 612a Third linear portion 612b Fourth linear portion 220, 620 Ground conductor 630 Substrate 231 First matching circuit 232 Second matching circuit 241-1 First antenna element side Line 241-2 First wave source side line 242-1 Second antenna element side line 242-2 Second wave source side line 300, 700 Equivalent circuit of antenna model with matching circuit 310, 710 Antenna 320-1 First Circuit 720-1 first matching circuit 320-2 second circuit 720-2 second matching circuit 330 wave source 321-i matching circuit 322-i first line 323-i second line 400 equivalent of transmission line Circuit 321a, 321b, 321c Matching element 500 Equivalent circuit of single antenna model 800 Screen display 810, 820, 83 Display area 900 computer 901 input device 902 reader 903 communication interface 904 HDD
905 CPU
906 RAM
907 ROM
908 Display device 909 Bus

Claims (3)

Creating an antenna model including an antenna including a plurality of antenna elements and a matching circuit connected to each of the plurality of antenna elements, the matching circuit including a matching element including a parasitic reactance and a loss resistance;
Obtaining the characteristics of the antenna and the matching element;
Calculate the characteristics of the created antenna model using the acquired characteristics of the antenna and the characteristics of the matching element,
Determining whether the calculated characteristics of the antenna model satisfy a desired standard value;
The computer executes a process to display the determined result,
The characteristic of the antenna model includes an S parameter of the antenna and the total efficiency of the antenna model, the characteristic of the matching element includes an impedance of the matching element, and the characteristic of the antenna model is an S of the antenna model. Including parameters,
In calculating the characteristics of the antenna model, the computer
The F parameter of the antenna is calculated using the S parameter of the antenna, the F parameter of the matching circuit is calculated using the impedance of the matching element, and the calculated F parameter of the antenna and the F parameter of the matching circuit are calculated. To calculate the S parameter of the antenna model using
The ratio of the radiation efficiency of the antenna and the sum of the loss of the antenna and the radiation efficiency is considered to be the same in the model of the antenna alone and the antenna model, and the total efficiency of the antenna model is calculated.
Antenna design method. When the matching element is mounted in parallel to the antenna, the computer calculates the inductance of the via connected to the matching element, and uses the calculated via inductance to determine the characteristics of the antenna model. calculating, antenna design method according to claim 1. The antenna design method according to claim 1, wherein the computer displays power consumption of the matching element when determining that the characteristics of the antenna model do not satisfy the desired standard value.